Abstract: Through the analysis of two torrential rains at June 20 and 19 August, 2015, in Nyingchi. Our analyses are based on conventional observation data, ground automatic station data, radar wind profile, satellite images, and 1°×1°reanalysis data of NCEP. These two torrential rains display different situation: the former occurs in subtropical stable sedentary circulation background and unstable energy increasing processes. The latter occurs in the circulation situation of a shear line which is formed between Iran high pressure and deputy high pressure, and unstable energy releasing processes. Both of the processes perform intensive moisture transportation in low-level rainfall areas, strong development of vertical movement, convergence in middle and lower troposphere, and divergence in high-level. Besides, the intensity of heavy rainfall as well as vertical drop area are consistent with strong vertical upward movement, strong convergence in low-level and strong divergence in high-level, and convergence center of moisture flux. However, the latter behaves obvious downstream processes of cold air, intensive high-and low-level jet, lower cloud top temperature, higher convective system development, the center of cloud-top temperature below-60℃ and stays longer. And torrential rains appears in the low center of cloud-top temperature and its gradient large value area.